ENTRY D6125 20120328 D082D612500000001 SUBENT D6125001 20120328 D082D612500100001 BIB 13 63 D612500100002 TITLE Measurement of fission excitation functions in 11B, D612500100003 16O,19F+232Th reactions in the extreme sub-barrier D612500100004 energy region D612500100005 AUTHOR (D.M.Nadkarni, A.Saxena, D.C.Biswas, R.K.Choudhury, D612500100006 S.S.Kapoor, N.Majumdar, P.Bhattacharya) D612500100007 INSTITUTE (3INDTRM,3INDSAH) D612500100008 REFERENCE (J,PR/C,59,R580,1999) D612500100009 FACILITY (VDGT,3INDTAT) BARC-TIFR 14UD Pelletron accelerator D612500100010 SAMPLE A self supporting 1.8 mg/cm**2 thick 232Th target D612500100011 DETECTOR (PS,MWPC) Two low pressure X-Y position sensitive D612500100012 multiwire avalanche counters of Breskin-type, having D612500100013 active dimensions of 6.5 cm x 5.0 cm and 15 cm x D612500100014 3.5 cm, were mounted on either side of the fissile D612500100015 target for detecting the complementary fission D612500100016 fragments in coincidence. D612500100017 The position sensitive detectors were kept at 14 cm D612500100018 and 12 cm, respectively, from the target subtending D612500100019 the in-plane angles of about 26 deg and 63 deg, D612500100020 respectively, at the target. D612500100021 The detectors were moved to different specified angles D612500100022 (33 deg, 200 deg), (75 deg, 253 deg) with respect to D612500100023 beam direction to carry out the measurements over a D612500100024 large angular range. D612500100025 The detectors were operated with isobutane gas at torr D612500100026 pressure. D6125 1 30 D612500100027 (SI) A 500 micron-thick semiconductor detector was D612500100028 placed at 25 deg at a distance of 40 cm from the D612500100029 target to monitor the elastically scattered heavy D612500100030 ions for normalization purposes. D612500100031 METHOD (COINC) Fusion-fission and transfer fission events D612500100032 were separated by folding angle technique and the D612500100033 fission cross sections have been measured employing D612500100034 the kinematic coincidence. D612500100035 The time of arrival of the fragments at the two D612500100036 position sensitive detectors and the X and Y position D612500100037 pulses from the two detectors were recorded event by D612500100038 event in list mode. D612500100039 PART-DET (FF) D612500100040 ANALYSIS (INTAD) The angle calibration of the fission fragment D612500100041 detectors was achieved from the observed dips in the D612500100042 fragment yields in the detectors due to the shadowing D612500100043 caused by the wires used to support the thin windows D612500100044 of the PSDs. D612500100045 This calibration was done using a 252Cf source mounted D612500100046 at the point of the target location. D612500100047 The coincidence timing information from the two D612500100048 fission fragment detectors was recorded as one of the D612500100049 parameters to select the genuine fission events time D612500100050 difference between the two FFs <20 ns and thus helped D612500100051 to reject random coincidences. D612500100052 From the event-by-event information on the position of D612500100053 the two complementary fragments in the two detectors, D612500100054 their angles of emission were calculated. D612500100055 The measured folding angle distributions at different D612500100056 bombarding energies were fitted with three D612500100057 Gaussian peaks corresponding to fusion-fission, D612500100058 transfer fission and low momentum transfer fission D612500100059 events. D612500100060 ERR-ANALYS (DATA-ERR) Total error consists of statistical error D612500100061 and errors on solid angle. D612500100062 STATUS (TABLE) Data were received from Dr.A.Saxena D612500100063 HISTORY (20110404C) Megha Bhike, Y. Santhi Sheela D612500100064 (20120328U) On. Finalized D612500100065 ENDBIB 63 0 D612500100066 COMMON 1 3 D612500100067 ANG-NRM D612500100068 ADEG D612500100069 25. D612500100070 ENDCOMMON 3 0 D612500100071 ENDSUBENT 70 0 D612500199999 SUBENT D6125002 20120328 D082D612500200001 BIB 2 5 D612500200002 REACTION 1(90-TH-232(5-B-11,F),,SIG,,MSC) D612500200003 fusion-fission cross section D612500200004 2(90-TH-232(5-B-11,F),,SIG,,MSC) D612500200005 transfer-fission cross sections D612500200006 MONITOR (90-TH-232(5-B-11,EL)90-TH-232,,DA,,RTH) D612500200007 ENDBIB 5 0 D612500200008 NOCOMMON 0 0 D612500200009 DATA 5 15 D612500200010 EN-CM DATA 1DATA-ERR 1DATA 2DATA-ERR 2 D612500200011 MEV MB MB MB MB D612500200012 61.08 668. 1. 9.05 0.1 D612500200013 59.15 581. 0.8 16.2 0.2 D612500200014 57.25 351. 0.5 4.33 0.1 D612500200015 56.8 450. 0.4 2.99 0.04 D612500200016 55.3 229. 0.5 10.7 1.0 D612500200017 52.0 107.83 0.4 1.72 0.05 D612500200018 51.45 117.0 0.3 1.17 0.03 D612500200019 49.52 31.3 0.1 0.23 .006 D612500200020 47.56 8.31 0.07 .045 .003 D612500200021 47.2 3.755 .03 .041 .003 D612500200022 46.6 2.65 .01 D612500200023 45.2 .254 .005 .0037 .0006 D612500200024 44.68 .207 .006 .0017 .0003 D612500200025 42.4 .00051 .00009 .000236 .00007 D612500200026 39.83 .0002 .00009 .0002 .00009 D612500200027 ENDDATA 17 0 D612500200028 ENDSUBENT 27 0 D612500299999 SUBENT D6125003 20120328 D082D612500300001 BIB 2 5 D612500300002 REACTION 1(90-TH-232(8-O-16,F),,SIG,,MSC) D612500300003 fusion-fission cross section D612500300004 2(90-TH-232(8-O-16,F),,SIG,,MSC) D612500300005 transfer-fission cross sections D612500300006 MONITOR (90-TH-232(8-O-16,EL)90-TH-232,,DA,,RTH) D612500300007 ENDBIB 5 0 D612500300008 NOCOMMON 0 0 3 D612500300009 DATA 5 5 D612500300010 EN-CM DATA 1DATA-ERR 1DATA 2DATA-ERR 2 D612500300011 MEV MB MB MB MB D612500300012 70.97 0.083 0.009 0.0138 0.005 D612500300013 69.08 0.061 0.004 0.0011 0.0007 D612500300014 67.31 0.0019 0.0003 0.00023 0.00006 D612500300015 64.48 0.0012 0.00009 0.0016 0.0004 D612500300016 59.76 0.0015 0.00003 0.00006 0.00002 D612500300017 ENDDATA 7 0 D612500300018 ENDSUBENT 17 0 D612500399999 SUBENT D6125004 20120328 D082D612500400001 BIB 2 5 D612500400002 REACTION 1(90-TH-232(9-F-19,F),,SIG,,MSC) D612500400003 fusion-fission cross section D612500400004 2(90-TH-232(9-F-19,F),,SIG,,MSC) D612500400005 transfer-fission cross sections D612500400006 MONITOR (90-TH-232(9-F-19,EL)90-TH-232,,DA,,RTH) D612500400007 ENDBIB 5 0 D612500400008 NOCOMMON 0 0 D612500400009 DATA 5 15 D612500400010 EN-CM DATA 1DATA-ERR 1DATA 2DATA-ERR 2 D612500400011 MEV MB MB MB MB D612500400012 85.3 15.67 .01 3.51 .055 D612500400013 84.4 10.14 .01 2.04 .045 D612500400014 81.6 1.54 .02 .66 .012 D612500400015 79.7 1.78 .035 1.22 .03 D612500400016 78.8 .36 .010 .13 .005 D612500400017 77.9 .195 .005 .27 .006 D612500400018 77.0 .101 .007 .0714 .009 D612500400019 75.0 .014 .001 .02 .004 D612500400020 74.2 .003 .0004 .039 .0015 D612500400021 73.2 .0051 .00055 .0051 .0004 D612500400022 72.3 .0017 .00022 .008 .00057 D612500400023 70.4 .0006 .00011 .0053 .00031 D612500400024 66.7 .00016 .00005 .0015 .00015 D612500400025 65.7 .0005 .0001 .00012 .00005 D612500400026 64.8 .00010 .00004 .00020 .00005 D612500400027 ENDDATA 17 0 D612500400028 ENDSUBENT 27 0 D612500499999 ENDENTRY 4 0 D612599999999